diff --git a/paddle/fluid/train/custom_trainer/feed/monitor/auc_monitor.cc b/paddle/fluid/train/custom_trainer/feed/monitor/auc_monitor.cc
index 9f20e3b569a376daa94409b7f620ac02739ce1cd..17eefce96551102bdf6d5aed056415cd4547011a 100644
--- a/paddle/fluid/train/custom_trainer/feed/monitor/auc_monitor.cc
+++ b/paddle/fluid/train/custom_trainer/feed/monitor/auc_monitor.cc
@@ -13,14 +13,8 @@ int AucMonitor::initialize(const YAML::Node& config, std::shared_ptr<TrainerCont
         _table_size = config["table_size"].as<int>();
     }
     set_table_size(_table_size);
-    _compute_interval = 3600;
     if (config["compute_interval"]) {
-        uint32_t interval = config["compute_interval"].as<uint32_t>();
-        if (interval != 3600 || interval != 86400) {
-            LOG(FATAL) << " AucMonitor config compute_interval just support hour: 3600 or day: 86400. ";
-            return -1;
-        }
-        _compute_interval = interval;
+        _compute_interval = config["compute_interval"].as<uint32_t>();
     }
 }
 
@@ -80,8 +74,7 @@ std::string AucMonitor::format_result() {
     if (fabs(_predicted_ctr) > 1e-6) {
         copc = _actual_ctr / _predicted_ctr;
     }
-    char buf[10240];
-    snprintf(buf, 10240 * sizeof(char), "%s: AUC=%.6f BUCKET_ERROR=%.6f MAE=%.6f RMSE=%.6f "
+    return paddle::string::format_string("%s: AUC=%.6f BUCKET_ERROR=%.6f MAE=%.6f RMSE=%.6f "
         "Actual CTR=%.6f Predicted CTR=%.6f COPC=%.6f INS Count=%.0f",
         Monitor::_name.c_str(), 
         _auc,
@@ -92,8 +85,6 @@ std::string AucMonitor::format_result() {
         _predicted_ctr, 
         copc,
         _size);
-
-    return std::string(buf);
 }
 
 void AucMonitor::add_unlocked(double pred, int label) {
diff --git a/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.cc b/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.cc
index f4b48f28d68532660a8d6c47401cf397acf4ce8a..0f8b17b76815980121b6dafaf3224b7173c5d258 100644
--- a/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.cc
+++ b/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.cc
@@ -6,14 +6,8 @@ namespace feed {
 
 int CostMonitor::initialize(const YAML::Node& config, std::shared_ptr<TrainerContext> context_ptr) {
     Monitor::initialize(config, context_ptr);
-    _compute_interval = 3600;
     if (config["compute_interval"]) {
-        uint32_t interval = config["compute_interval"].as<uint32_t>();
-        if (interval != 3600 || interval != 86400) {
-            LOG(FATAL) << " AucMonitor config compute_interval just support hour: 3600 or day: 86400. ";
-            return -1;
-        }
-        _compute_interval = interval;
+        _compute_interval = config["compute_interval"].as<uint32_t>();
     }
 }
 
@@ -36,14 +30,6 @@ bool CostMonitor::need_compute_result(int epoch_id, EpochAccessor* accessor) {
     return true;
 }
 
-std::string CostMonitor::format_result() {
-    char buf[1024];
-    snprintf(buf, 1024 * sizeof(char), "%s: Cost Time=%lu", 
-            Monitor::_name.c_str(),
-            _avg_time_ms);
-    return std::string(buf);
-}
-
 }  // namespace feed
 }  // namespace custom_trainer
 }  // namespace paddle
diff --git a/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.h b/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.h
index 56a0ecfbe1a33ff659be1b189b56a89e2bbb444a..22815355fdb9184fcc6b36367e30584014a8b972 100644
--- a/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.h
+++ b/paddle/fluid/train/custom_trainer/feed/monitor/cost_monitor.h
@@ -10,7 +10,7 @@ namespace feed {
 // cost time profile
 class CostMonitor : public Monitor {
 public:
-    CostMonitor() : _total_time_ms(0), _total_cnt(0), _avg_time_ms(0) {}
+    CostMonitor() : _total_time_ms(0), _total_cnt(0), _avg_time_ms(0), _compute_interval(0) {}
     virtual ~CostMonitor() {}
 
     virtual int initialize(const YAML::Node& config,
@@ -30,7 +30,10 @@ public:
         _avg_time_ms = _total_time_ms / _total_cnt;
     }
     //基于现有结果，输出格式化的统计信息
-    virtual std::string format_result();
+    virtual std::string format_result() {
+        return paddle::string::format_string(
+                "Monitor %s: Cost Time=%lu", Monitor::_name.c_str(), _avg_time_ms);
+    }
     
     virtual void reset() {
         _total_time_ms = 0;